WRITING AND READING 7.5 GBITS IN(2) LONGITUDINAL QUANTIZED MAGNETIC DISK USING MAGNETIC FORCE MICROSCOPE TIPS/

Quantized magnetic disks (QMDs) consisting of longitudinal single-doma in Ni bars with densities from 3 Gbits/in(2) to 10 Gbits/in(2) were fa bricated using nanoimprint lithography and a lift-off process. Two dif ferent types of MFM tips were used in the writing and reading process, one for erasing and writing, another for reading; both were magnetica lly 'hard'. The QMDs were first erased by aligning all bars with the w rite-tip scanning the entire sample, then written using lithography so ftware in Nano-Scope III. Error-free results were obtained up to 7.5 G bits/in(2) despite the poorly-defined magnetic field from the write-ti p and despite not having a feedback control for the write-tip position .